Pressure-fluid-actuated tool



Nov. 2 ,1926. 1,605,076

E. H. SHAFF PRESSURE FLUID ACTUATED TOOL Filed Dec. 6. 1920 FIG-l J6 432 9 Patented Nov. 2, 1926.

UNITED srarss PATENT OFFICE.

ERNEST H. SHAFF, OF GRAND HAVEN, MICHIGAN, ASSIGNOR TO WILLIAM H.

KELLER,

INCL, OF GRAND HAVEN, MICHIGAN, A CORPORATION OF MICHIGAN.

PRESSURE-FLUID-ACTU'ATED TOOL.

Application filed December 6,1920. Serial No. 428,429,

The invention has general reference to pressure-fluid-actuated tools andmore particularly to tools of this class commonly known as jambriveters. 'Such riveters are especially constructed for use in limitedor restricted spaces and while the cylinders are made of relativelyshort length their internal diameters are relatively large so that thevolumetric capacity of the cylinder is substantial. When, therefore, thesupply of motive fluid is not maintained at high pressure, as isfrequently the case because of a long and restricted air-line, the rapidand relatively free expansion thereof when admitted to the rear endofthe cylinder to drive the piston forwardly results in a sudden drop inpressure in the cylinder.

It is common practice in tools of this character to utilize a portion ofthe motive fluid admitted to the rear end of the cylinder, for shiftingthe valve member as the piston approaches the forward limit of itsmovement, the flow of the motive fluid being controlled by the piston inits movement. I have found that in the case of large capacity cylinders,as, for instance, those of jamb riveters, above referred to, the returnmovement of the valve member by the pressure fluid admitted to thecylinder to drive the piston forwardly, is not sufficiently rapid orpositive for the eflicient operation of the tool.

The primary object of my invention, therefore, is to provide improvedmeans for effecting the positive rearward movement of the valve memberand thus improve the efficiency of the tool.

More specifically stated, the invention has for its aim the provision ofmeans controlled by the initial rearward movement of the valve memberfor admitting pressure fluid directly from the source of supply to thevalve member whereby to insure that it shall be shifted speedily andpositively to its rearward position.

A further object is to deflect such live motive fluid from the valvemember, after effecting the rearward movement thereof to the forward endof the cylinder to return the piston, thus relieving the valve memberfrom the force of such pressure fluid and permitting its reverse orforward movement.

Other and incidental objects of the invention include the provision of apractical tool of simplified construction and arrangement.

In the accompanying drawings, in which I have illustrated a preferredembodiment of my invention, Figure 1 is a central vertical sectionalview through a tool of the jamb riveter type. Fig. 2 is a similar viewbut showing the valve member shifted into a po sition to efi'ect thereturn of the piston.

The tool comprises generally a cylinder 3 having a piston chamber 4 inwhich a piston 5 is reciprocable into and out of engagement with a rivetset 6. 7 designates generally the valve mechanism for controlling thepiston. The cylinder is mounted within a housing 8 so as to be movableforwardly therein under the action of pressure fluid admitted into therear end of the housing which is closed by a cap 9. A passageway 10 forpressure fluid is provided by a stem portion 11 of the cap into which asuitable handle (not shown) is adapted to be entered, such handle beingprovided with the usual motive fluid controlling valve.

The cylinder 3 is arranged to fit neatly at its rear end within thehousing 8, and at its forward end is reduced in diameter to providebetween it and the housing an exhaust chamber 12. At its forward end thehousing is shaped to provide an inturned annular boss 13 for slidablyengaging the periphery of the forward end of the cylinder and closingtheforward end of the chamberlQ; A port 14 leads from the forward end ofsaid chamber 12 to the atmosphere.

The cylinder 3 is made of relatively short length, but of comparativelylarge internal diameter to provide the piston chamber 4. The piston 5 isalso made of relatively short length, and in the operation of the toolengages the rivet set 6 or other tool mounted in the forward end of thecylinder Any suitable means may be employed to retain the rivet set inposition such, for example, as that illustrated generally at 15.

-The valve mechanism comprises a casing 16 composed of twoannula-rinterlitting sections 16 and 16 entered within the rear end of thecylinder in axial alinement with the piston chamber and held in positionby means of an end plug 17 screw-threaded into the rear endof thecylinder. The sections of the casing 16 are preferably rabbeted so as tointerflt, and to receive the casing the rear end of the cylinder isformed with an enlarged bore providing a shoulder 16 against which theforward section 16 of the casing is held by theplug 17. The casing 16 isso arranged within the cylinder that a portion of the rear end of thecylinder protrudes rearwardly beyond the casing sufficiently to receivesaid plug. Suitable means mav be 6111310 ed for loclrin the alu inposition within the rear end of the cylinder. Such means may, forexample, comprise a spring clip 18 having a stem portion 19 adapted toenter registering radial grooves 20 and 21 in the rear end of thecylinder and in the rear face of the plug, respectively. This locliingmeans is covered in my copending application Serial No. 427,687, filedDecember 2, 1920, and therefore is not illus trated and described indetail nor claimed herein. The registering grooves 20 and 21 alsoprovide a passage establishing communication between the passageway 10and a chamber 22 formed between the cap 9 and the rear face of the plug17. Pressure fluid is thus admitted constantly to the chamber 22 andacts upon the cylinder to force it forwardly in the housing 8 as limitedby the space within which the tool is being used.

For the purpose of sealing the joint between the rear end of thecylinder and the housing, 1 preferably provide an annular packing membersuch as a leather ring 23 entered in an annular groove 24 which isformed in the periphery of the cylinder and communicates by way of aduct 25 with the rear chamber 22. Itwill be seen that pressure fluidacting upon the ring 23 will expan'd it into engagement with the innerperiphery of the housing and thus provide an effective seal betweenthese relatively movable parts.

The valve casing 16 is shaped upon its inner periphery to provide avalve chamber coaxially of the piston chamber, in which a valve member26 is reciprocable to control the admission and exhaust of pressurefluid to and from the cylinder and thereby to effect the reciprocationof the piston. in the rear end of the casing 16 there is provided anannular groove 27 communicating by way of a duct 28 with an annulargroove 29 in the forward face of the plug 17. The latter is in constantcommunication by way of a port or ports 30 with the rear pressurechamber 22, so that pressure fluid is constantly present in the annulargroove 29 and in the duct 28. The groove 27 in the inner periphery ofthe casing is adapted to be controlled by the rear end of the valvemember 26.

An annular rear pressure chamber 31 is rovided at the rear of the valvechamber between the valve member and its casing. This chamber 31 is inconstant communication by way of a port 32 with the duct 28. The forwardwall of said pressure chamber is formed by a flange 33 on the peripheryof the valve member, and such wall constitutes the smaller pressure areaof the valve member against which the pressure fluid in the chamber 31constantly acts to shift the valve member 26 forwardly in the casing.

When the valve member 26 is thus shifted forwardly into the positionwhich it occupies in Fig. 1, pressure fluid is admitted to the rear endof the cylinder from the chamber 22 by way of the port 80, duct 28 andgroove 27, and the piston is driven forwardly under the expansion of thehigh pressure fluid. As the piston approaches the forward end of thecylinder the air or other pressure therein is permitted to exhaust fromthe forward end of the piston chamber by way of a longitudinalpassageway 34 opening into the forward end of said chamber and extendingrearwardly through the wall of the cylinder and into the valve casingsection 16 from whence it opens into an annular chamber 35 provided by agroove in the inner periphery of said casing section. The latter grooveis connected, in the forward position of the valve member, with asimilarly formed chamber 36 by an annular groove 37 formed in the outerperiphery of the valve member at the forward end thereof. The chamber 36communicates by way of an exhaust passage 38 with the exhaust chamber12. Thus, in the forward movement of the piston, air or other pressurein the forward end of the piston chamber is permitted to escape to theatmosphere by way of the passage 8st, chamber 35, groove 37, chamber 36,exhaust passage 88 and exhaust chamber 12.

A passage way 39 extends from substantially the center of the pistonchamber rearwardly into the valve casing, and its rear end opens intothe valve chamber through a transverse groove 39 Said groove is closedby the valve member in the rearward position thereof, and is connected,in the for ward position of the valve member, by a groove 89 with anannular pressure chamber 40 formed by means of an annular groove in theinner periphery of the casing 16. The valve member is provided with aperipheral flange 11 operable in said annular chamber 40, the forwardside of said flange providing the larger pressure area of the valvemember. As the piston in its forward movement uncovers the forward endof the passage 39, a portion of the pressure fluid admitted to the rearend of the cylinder to drive the piston forwardly, passes by way of thetransverse groove 39 and the groove 39" into the annular chamber 10, andacts upon the larger pressure area of the valve member to force thelatter rearwardly against the action of the pressure fluid acting uponthe smaller pressure area in the annular chamber 31. After the initialrear ward movement of the valve member, the pressure fluid admitted tothe passageway 39 is assisted by pressure on the extreme forward end ofthe valve member until the annulan groove36 isuncovered, whereupon thepressure fluid in the rear piston chamber exhausts through the annulargroove 36 and the exhaust passage 38. r I Leading from near the forwardend of the piston chamber and also extending rearwardly to the annularchamber 40 is a passageway 42 whose opening into the piston chamber isso arrangedas to be closed by the piston in the forward position of thelatter. In its initial movement rearwardly the flange 41 of the valvemember also uncovers a radial port 43 leading from the annular chamber40 to a longitudinal passage 44 provided in the valve casing andcommunicating at its rear end with the annular groove 29. The port 43 isthus in constant communication with the supply of motive fluid, and assoon as the flange 41 partially uncovers the port in the rearwardmovement of the valve, live pressure fluid is admitted to the chamber 40and to the larger pressure area of the valve member. At this time theforward end of the passageway 42 is closed so as to prevent the escapeof the live pressure fluid from the chamber 40. This pressure fluid,therefore, acts to positively shift the valve member rearwardly to theposition shown in Fig. 2 and to hold it firmly in such position.

In such rearward movement of the valve member, the transverse groove 39in the valve casing is closed by the valve member so as to prevent theflow of pressure fluid from the chamber 40 into the cylinder through thepassageway 39; and communication between the annular chambers and 36 atthe forward end of the valve casing by way of the annular peripheralgroove 37 in the valve member is cut off. At the same time communicationis established between the annular chamber 35 and a radial passage 45leading to the forward end of the passage 44 which communicatesconstantly with the source of pressure fluid supply. The chamber 35communicates at all times by way of a port 35 with the longitudinalpassageway 34 leading into the forward end of the cylinder. Hence, itwill be observed, in this position of the valve member the live pressurefluid admitted to the passage 44 is deflected from the valve member bybeing discharged into the forward end of the piston chamber to returnthe piston. More over, as the piston in its rearward movement uncoversthe forward end of the passageway 42, motive fluid in the annularchamber passes to the forward end of the piston chamber to assist inreturning the piston.

In order that the pressure in the rear end of the piston chamber shallbe permitted to escape to enable the free returnof the piston, theannular chamber 36 in the forward end of the valve casing is placed incommunication with the piston chamber in such is cut off.

By reason of the flow of pressure fluid throu h the assa 'es 44 and andoassa eb p 2:: I l D way 34, and through the passageway 42, to

the forward end of the cylinder to return pressure 1n the annularchamber.

the piston, 40 is relieved sufficiently to enable the pressure fluidacting upont-he smaller pressure area of the valve member to again shiftthe latter forwardly whereby to again admit pressure fluid into the rearend of the cylinder to drive the piston forwardly for an other cycle ofoperation.

To facilitate the rearward movement of the valve member, 1 preferablyprovide a port 46'leading from the piston chamber just forwardly of thevalve casing to the an nular chamber 31.' Since the valve member in itsrearward movement uncovers the an nular chamber 36 at the forward end ofthe valve casing, pressure fluid entering the annular chamber 31 fromthe port 32 is permitted to exhaust from said chamber to the passage '38by way of the piston chamber. The port 46 being made of larger apacitythan the port 32, the pressure in the cham ber 31 is quickly relieved.

A summary of the operation of the tool is as follows: Assuming the partsto be in the position shown in Fig. 1, pressure fluid is admitted fromthe passage 10 through the radial grooves 20 and 21 into the chamber 22between the cylinder and the cap 9. Pres sure fluid is thus admitted bythe port 32 to the smaller pressure area of the valve to holdit in itsforward position. At thesame time, the motive fluid enters the rear endof the piston chamber by way of the annular groove 27 and drives thepiston forwardly therein, the air or pressure in the forward end of thepiston chamber exhausting by way of passageway 34, annular chambers 35and 36, which are connected by the groove 37, to the exhaust passage 38.

In the forward travel of the piston, pres sure fluid is admitted to thechamber 0 and exerts pressure upon the valve members larger pressurearea tending to force it rearwardly. When the piston has uncovered theforward end of the passageway 39, 3res sure fluid is admitted from theinterior of is permitted to exhaust to the atiii] the'piston chamber tothe annular chamber 40. The valve member is thus given an initialrearward movement, whereupon the extreme forward end of the valve memberis exposed to the pressure fluid in the rear piston chamber. As this endof the valve member has a larger surface area than the rear end of thevalve member the action of pressure fluid thereon assists in therearward movement of the valve. The port as, communicating constantlywith the source of pressure fluid supply, is uncovered by the flange 41of the valve member, whence live pressure fluid is admitted to thechamber 40 and the valve member positively shifted rearwardly. In such arearward position of the valve member, the flow of motive fluid into thecylinder by way of the passageway 39 is prevented since the transversegroove 39 is closed by the valve member.

Upon the completion of such rearward movement of the valve member, theflow of pressure fluid to the rear end of the piston chamber is cut offand pressure fluid admitted to the forward end of the piston chamber byway of the passages 4a and 45, annular chamber 35, port 35 and passageway 34 to return the piston. As the piston travels rear'wardly, pressurein the rear end of the piston chamber escapes to the atmosphere by wayof the annular chamber 36 which communicates with the exhaust passage38, communication between the chamber 36 and the interior of the pistonchamber having been established by therearward movement of the valvemember. The rearward movement of the valve member was furtherfacilitated by the release of pressure from the annular chamber 31 byway of the port 46 and thence through the piston chamber to the exhaustpassage 38.

The pressure in the annular chamber 40 having been relieved by the flowof live pressure fluid to the forward end of the cylinder through thepassages 4a and 4:5, and the rear end of the ports 16 having been closedby the flange 33 of the valve member, live pressure fluid admitted tothe annular chamber 31 by way of the port 32 shifts the valve memberforwardly so as to admit pressure fluid into the rear end of thecylinder and drive the piston forwardly therein.

It will be seen that I have provided a pressure-fluid-actuated tool of ahighly practical character. The construction is exceedingly simple andthe operation efficient. The admission of live pressure fluid to thevalve member under the control thereof, serves to insure that it willmove speedily and positively to its rearward position even though a highline pressure is not constantly maintained. Moreover, the deflection ofthe pressure fluid from the valve member to the forward end of thepiston chamber to return the' piston, facilitates the forward movementof the valve member under the action of live pressure fluid from thesource of supply.

It is to be understood that while I have herein illustrated anddescribed the invention as applied to a jamb riveter, I contemplate theapplication of the invention to other tools of this general class. Ialso desire to have it understood that the invention is not to belimited, in the interpretation of the appended claims, to the details ofconstruction and arrangement set forth, except as may be necessitated bythe state of the prior art.

I claim as my invention:

1. A pressure fluid actuated tool having a piston chamber, a pistonreciprocable in said chamber, a hollow valve member axially alined withthe rear end of said chamber and adapted to receive the piston, apassage opening into the piston chamber substantially centrally thereofand arranged to be uncovered by the piston in its forward stroke, alarge pressure chamber for the valve member, said valve member beingadapted when in its forward position to connect said pressure chamberwith the rear end of said passage and to cut off such communication whenin its rcarmost position, and means operable during the initial portionof the rearward movement of the valve member to admit live motive fluidto said pressure chamber whereby to complete the rearward movement ofthe valve member.

2. A. pressure fluid actuated tool having a reciprocating piston and areciprocating valve, means operable in the forward stroke of the pistonto admit pressure fluid to impart an initial movement only to the valvemember, said admission of pressure fluid being cut off by such initialmovement of the valve member, and means operable upon the initialmovement of the valve member to admit live motive fluid to the valve tocomplete its shifting movement.

3. A pressure fluid actuated tool having a. reciprocating piston and areciprocating valve, means operable in the forward stroke of the pistonto admit pressure fluid to impart an initial movement only to the valvemember, said admission of pressure fluid being cut off by such initialmovement of the valve member, means operable upon the initial movementof the valve member to admit live motive fluidto the valve to completeits shifting movement, and a passage opening into the forward end of thepiston chamber and associated with the last mentioned means whereby whenthe valve member moves into its rearmost position motive fluid isadmitted to the forward piston chamber to return the piston.

4-. A pressure fluid actuated tool having a reciprocating piston and areciprocating valve, means controlled by the piston in its forwardstroke for admitting pressure fluid to impart an initial rearwardshifting movement to the valve, the valve in its said movement cuttingoff said admission of pressure fluid and rendering the said meansinoperative, and means operable when said first mentioned means isrendered inoperative to admit live motive fluid to the valve to completeits shifting movement.

5. A pressure fluid actuated tool having a reciprocating piston and areciprocating valve, means controlled by the piston in its forwardstroke for admitting pressure fluid to impart an initial rearwardshifting movement to the valve, said means being also controlled by thevalve in. its said movement to cut off said admission of pressure fluidwhereby to render the said means inoperative, means operable when saidfirst mentioned means is rendered inoperative to ad mit live motivefluid to the valve to complete its shifting movement, and means forrelieving pressure in the rear piston chamber during the latter portionof the movement of the valve.

6. A pressure fluid actuated tool having a reciprocating piston and areciprocating valve, means including a passage controlled by the pistonin its forward stroke for ad mitting pressure fluid to impart an initialrearward shifting movement to the valve,v

said passage being closed by the valve in its said movement, therebyrendering said means inoperative, means operative when said firstmentioned means is rendered inoperative to admit live motive fluid tothe valve to complete its shifting movement, means operable upon suchinitial shifting movement of the valve to expose the forward end of thevalve member to the pressure fluid in the piston chamber, and meansoperable during the final portion of the movement of the valve torelieve the pressure in the rear piston chamber.

7. A pressure fluid actuated tool comprising, in combination, a cylinderhaving a piston reciprocable therein, a valve casing, a valvereciprocable in said valve casing, means to permit pressure fluid toreciprocate said. piston, including an inlet passage to the forward endof said cylinder controlled by said valve, said inlet passage includinga longitudinal passage in said valve casing constantly in communicationwith live motive fluid, means to reciprocate said valve including aperipheral flange on said valve, an annular chamberin said valve casingadjacent said flange, an inlet passage to said chamber controlled bysaid piston and adapted to admit pressure fluid from the cylinder toshift the valve rearwardly during the forward movement of the piston anda second inlet passage to said chamber to admit live pressure fluid tomove the valve rearwardly including aport connecting said chamber with apoint in said passage in the valve casing, said port being opened bysaid valve in its rearward movement, the arrangement being such thatupon completion of the rearward movement of the valve the pressure fluidthereby admitted to the forward end of the cylinder passes across theend of said port.

In testimony whereof, I have hereunto set my hand.

ERNEST H. SHAFF,

